patch 8.2.4043: using int for second argument of ga_init2()

Problem:    Using int for second argument of ga_init2().
Solution:   Remove unnessary type cast (int) when using sizeof().
diff --git a/src/usercmd.c b/src/usercmd.c
index 40790a1..2830a50 100644
--- a/src/usercmd.c
+++ b/src/usercmd.c
@@ -917,7 +917,7 @@
     {
 	gap = &curbuf->b_ucmds;
 	if (gap->ga_itemsize == 0)
-	    ga_init2(gap, (int)sizeof(ucmd_T), 4);
+	    ga_init2(gap, sizeof(ucmd_T), 4);
     }
     else
 	gap = &ucmds;